1. Field of the Invention
The present invention relates to an optical disc device capable of recording, in a disc corresponding to an existing data format standard, record data with high efficiency using a data format conforming to a standard having higher data format efficiency than the existing standard, and to an optical disc device for reading a disc recorded with high efficiency.
2. Description of the Related Art
The CD (compact disc) standard, and the DVD (Digital Versatile Disc) standard responding to demands for high capacity as well as ensuring mechanical compatibility by having the same disc diameter as a CD, are known as standards for optical discs for performing recording and reading optically using an optical head.
In a DVD drive for handling this DVD, upward compatibility with a CD is ensured and it is possible to read CDs also.
Recordable optical discs exist for both the CD and DVD systems, and the CD recording system is unified for CD-R (Recordable) and CD-RW (ReWritable), while the DVD recording system currently has various candidate standards and no de facto standard has yet been defined.
Regarding the recording capacity that can be recorded on a disc, compared to a CD, a DVD has an overwhelmingly larger capacity, and in conditions where data amount of files handled by a personal computer is increased, since the standard recording capacity of a CD-R or CD-RW is 650 MB (megabytes) or 700 MB, there are situations where this recording capacity is insufficient.
However, the CD standard recording methods are unified, as has been described previously, and CD-R/RW drives have become widespread, and therefore LSIs for recording system signal processing circuits for CD-R and CD-RW are available cheaply, and also discs for CD-R and CD-RW are cheaply available on the market.
A system has been proposed for, while adopting the CD standard data format, that is, CD modulation code (EFM) and error correction code (ECC), shortening the length of recording marks made up of pits and lands for recording on the disc, to increase the linear density compared to that of the standard and give increased disc recording capacity.